1. Field of the Invention
The present invention generally pertains to a mobile robot and more specifically to a mobile robot that has a geometrically symmetric modular body which has the agility and versatility to negotiate in a wide variety of applications utilizing front legs, back legs and body which independently rotate about a horizontal center axis.
2. Description of the Related Art
Currently mobile robots can be used in such mundane applications as floor polishing and vacuuming, to dangerous work such as cleanup of toxic waste, to exciting applications such as exploration of the moon and Mars. However, acceptance of mobile robots for the varied applications possible now and in the future is limited largely due to the high cost associated with development of such robots. Typically mobile robots are designed to do a specific task like those mentioned above. If another task is required, generally a new design is needed to accomplish the new task. This is an expensive approach. It is now appropriate that a more cost-conscious path be pursued. Robots intended for a variety of commercial applications will need compatibility of equipment and systems, as well as lower production costs, to make them economically feasible for use on a wide scale. This would be possible if a modular mobile robot body was available that was versatile and agile enough to adapt to new applications by combining the appropriate modules to accomplish the new task.
Attempts have been made to incorporate modularity into the design of mobile robots. Most of these designs simply start with a locomotion base at tile bottom of the robot and stack modules, one on top of the other, up from the base. This approach has limitations. The only direction for growth is up. The center of gravity becomes too high for many applications as more modules are added. The Nomad 200 by Nomadic Technologies, Inc. uses this approach, which is limited mainly to mobile robot research applications in a controlled environment on a flat surface. If robots are to be used in the real world they should be capable of navigating more than a flat surface in order to get to some of the placed they are needed, so agility is also a critical criterion for a useful mobile robot to possess.
Much effort has gone into making mobile robots agile enough to be used in environments humans and animals can navigate in with ease. Several designs incorporate some aspect of agility in them. U.S. Pat. No. 4,993,912 to King, Shackelord, and Kahl (1991) describes a robot which has the ability to climb stairs. The "Go-For" robot designed by NASA referred to in "1991 NASA PLANETARY ROVER PROGRAM" by David Lavery and Roger J. Bedard Jr. has the capability to maneuver into an upright position without assistance if it tips or gets knocked over. This is an important feature in some applications such as robotics exploration of the moon and Mars where physical assistance from man is not practical or possible. Rocky III also developed by NASA described in "1991 NASA PLANETARY ROVER PROGRAM" by David Lavery and Roger J. Bedard Jr. has the ability to traverse ragged terrain.
Another aspect relating to agility a robot needs is the ease at which the robots sensors and actuators can be maneuvered into positions for use. Currently mobile robots such as the robots referred to above have actuators and sensors located in specific location on the :front, back, bottom, and sides of the robot. Sometimes the same type of sensor or actuator is used in many different places because the robot is unable to maneuver that sensor into the other locations where use is desired. If the design of the mobile robot were such that actuators and sensors could be maneuvered more easily into other locations, this would cut down on duplication of sensors and actuators, which would cut down on weight and power consumption. A mobile robot body that shows increased agility and versatility over the prior art would have the ability to be used in a wider range of applications and, combined with a modular approach, would be more cost effective.